What properties distinguish laser light from typical light sources?

Correct Answer: B

Rationale: Laser light differs from typical light sources due to its monochromatic nature (single color) and coherence (synchronized waves). This means that laser light consists of a single wavelength and synchronized waves, unlike typical light sources that emit a range of wavelengths and are incoherent. The monochromatic nature of laser light allows it to be of a single color, while coherence ensures that the waves are synchronized. These unique properties of laser light make it valuable for a wide range of applications in fields such as medicine, industry, and research. Choices A, C, and D are incorrect because laser light's distinguishing features are not related to enhanced brightness, increased velocity, or limited visibility to the human eye. Instead, it is the monochromatic nature and coherence that set laser light apart from typical light sources.

Correct Answer: A

Rationale: Red blood cells, also known as erythrocytes, play a crucial role in the cardiovascular system by primarily transporting oxygen from the lungs to the body's tissues and organs. This essential function is carried out through the interaction of hemoglobin, a protein within red blood cells, which binds to oxygen in the lungs and releases it in the body's tissues. Choices B, C, and D are incorrect. Red blood cells are not actively involved in fighting infections, regulating blood clotting, or eliminating waste products from the body.

Correct Answer: A

Rationale: Exhalation (expiration) involves active muscle contraction, specifically the diaphragm and intercostal muscles, to decrease the volume of the thoracic cavity and push air out of the lungs. In contrast, inhalation (inspiration) is a passive process where the diaphragm and external intercostal muscles contract to increase the thoracic cavity volume, allowing air to flow into the lungs. Choice B is incorrect as exhalation removes carbon dioxide-rich air and inhalation brings in oxygen-rich air. Choice C is incorrect because both exhalation and inhalation can occur through the nose or mouth. Choice D is inaccurate as inhalation humidifies and warms the air, while exhalation cools and dries it.

Correct Answer: C

Rationale: A) Natural selection is a mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce, passing on those traits to the next generation. B) Genetic drift is a mechanism of evolution that occurs due to random changes in allele frequencies in a population. C) Lamarckism, also known as the inheritance of acquired characteristics, is a discredited theory that suggests organisms can pass on traits acquired during their lifetime to their offspring. This mechanism has been largely rejected by the scientific community. D) Mutation is a mechanism of evolution that introduces new genetic variation into a population, which can lead to the emergence of new traits and adaptations over time.

Correct Answer: C

Rationale: The correct answer is Vitamin D. Vitamin D is crucial for the proper absorption of calcium in the intestines and is essential for maintaining lung function. It regulates calcium and phosphorus levels, crucial for healthy bones and teeth. Vitamin A is important for vision and immune function, not specifically for calcium absorption or lung function. Vitamin B12 is essential for nerve function and red blood cell production, not related to calcium absorption or lung function. Vitamin E is an antioxidant that helps protect cells from damage, but it is not directly involved in calcium absorption or lung function.

Correct Answer: C

Rationale: When there is no external force acting upon an object, the law of conservation of momentum dictates that the momentum of the object remains constant. This means that the momentum does not increase or decrease; it stays the same. Choice A is incorrect because momentum does not increase. Choice B is incorrect because momentum does not decrease. Choice D is incorrect as momentum does not become zero; it remains constant as per the conservation law. Therefore, the correct answer is C, as the object's momentum is unchanged in the absence of external forces.

Correct Answer: D

Rationale: Sarcomeres are the fundamental contractile units of skeletal muscles and are responsible for muscle contraction. They consist of actin and myosin filaments that slide past each other during muscle contraction. Neurons are responsible for transmitting signals to and from muscles but are not directly involved in muscle contraction. Myofibrils are composed of sarcomeres and are the structures within muscle cells where muscle contractions take place. Tendons are connective tissues that attach muscles to bones and are not directly involved in muscle contraction.

Correct Answer: C

Rationale: The given electron configuration matches that of Argon, an element found in Group 18 of the periodic table. This element is in the third period, as indicated by the highest energy level (n=3) where electrons are present. Therefore, the correct answer is Group 18, Period 3. Choice A (Group 16, Period 3) corresponds to sulfur, not the given electron configuration. Choice B (Group 14, Period 3) corresponds to silicon, not the given electron configuration. Choice D (Group 17, Period 2) corresponds to chlorine, which is in Period 3 but not in Group 18, making it incorrect for the given electron configuration.

Correct Answer: C

Rationale: Stretch marks occur when the dermis layer tears due to rapid stretching of the skin. This tearing leads to the appearance of stretch marks, which are often red or purple at first and then fade to a silvery-white color over time. Inflammation of the dermis or clogging of sebaceous glands are not directly related to the formation of stretch marks. Therefore, choices A, B, and D are incorrect as they do not describe the actual cause of stretch marks.